Simulation of transport through soil of E. coli derived from livestock slurry using the macro model

Abstract. Leaching of faecal coliforms to rivers, lakes and groundwater following the spreading of animal slurry on land is of environmental and public health concern. A two-stage approach was adopted to modelling the transport processes by which Escherichia coli passes through the soil to receiving waters via field drains. First, parameter values were selected for the dual-porosity contaminant transport model macro to simulate through-soil flows, sorption and die-off of E. coli . These simulations reproduced experimental measurements showing rapid flows of the microorganisms to field drains after slurry spreading, which could be explained in terms of macropore flow in which trapping of colloids such as E. coli does not take place. Second, a series of predictive simulations was carried out to test the influence of soil and weather conditions on E. coli losses. These showed that losses are strongly influenced by soil wetness conditions at the time of spreading, and to a lesser degree by rainfall occurring soon after spreading. Selection of spreading 'workdays' with particular weather and soil wetness conditions is beneficial, which indicates opportunities for substantial reductions in the environmental risks of water pollution by E. coli and other faecal microorganisms.     

提高猪场沼液净化处理效果的氨吹脱控制参数

针对畜禽养殖场沼气工程沼液氨氮浓度高,碳氮比不足,直接采用传统生化污水处理法效果不佳的问题,该文对氨吹脱工艺降低猪场沼液氨氮浓度参数进行了试验研究,探索了不同初始氨氮浓度、pH值、气液比、温度等参数对氨氮去除的效果,并进一步研究了Ca(OH)2的混凝作用。结果表明:初始氨氮质量浓度分别为500和900mg/L时,氨氮去除率无显著差异。在初始氨氮质量浓度为900mg/L,pH值为10.5,气液比(流量比)2000,沼液温度30℃的运行条件下,氨氮去除率较高为81.84%。在Ca(OH)2投加量为5.0g/L条件下,混凝沉淀效果较好,化学需氧量(COD)、总磷(TP)和PO43-去除率分别为30.13%、97.44%和98.76%,但总硬度提高了106%。该文研究结果为开发沼液深度处理工艺提供了数据。     

禽畜粪便的固液分离方法与设备

禽畜粪便的固液分离是处理和利用禽畜粪便的重要环节之一。本文介绍了分离禽畜粪便的基本原理,综合分析了国内外各种分离设备的特点、结构形式、适用范围及不足之处,并就开发新的分离设备提出了建议。     

Nitrate leaching in an organic dairy/crop rotationas affected by organic manure type, livestock densityand crop

Abstract. In dairy farming systems the risk of nitrate leaching is increased by mixed rotations (pasture/arable) and the use of organic manure. We investigated the effect of four organic farming systems with different livestock densities and different types of organic manure on crop yields, nitrate leaching and N balance in an organic dairy/crop rotation (barley–grass-clover–grass-clover–barley/pea–winter wheat–fodder beet) from 1994 to 1998. Nitrate concentrations in soil water extracted by ceramic suction cups ranged from below 1 mg NO₃-N l^?1 in 1^st year grass-clover to 20–50 mg NO₃-N l^?1 in the winter following barley/pea and winter wheat. Peaks of high nitrate concentrations were observed in 2^nd year grass-clover, probably due to urination by grazing cattle. Nitrate leaching was affected by climatic conditions (drainage volume), livestock density and time since ploughing in of grass-clover. No difference in nitrate leaching was observed between the use of slurry alone and farmyard manure from deep litter housing in combination with slurry. Increasing the total-N input to the rotation by 40 kg N ha^?1 year^?1 (from 0.9 to 1.4 livestock units ha^?1) only increased leaching by 6 kg NO₃-N ha^?1. Nitrate leaching was highest in the second winter (after winter wheat) following ploughing in of the grass-clover (61 kg NO₃-N ha^?1). Leaching losses were lowest in 1^st year grass-clover (20 kg NO₃-N ha^?1). Averaged over the four years, nitrate concentration in drainage water was 57 mg l^?1. Minimizing leaching losses requires improved utilization of organic N accumulated in grazed grass-clover pastures. The N balance for the crop rotation as a whole indicated that accumulation of N in soil organic matter in the fields of these systems was small.     

高通量测序分析新疆沼液中发酵微生物的多样性

利用高通量测序技术研究了5种新疆不同地区的沼气池(A08,A09,A010,A011和A012)的微生物群落结构和多样性。获得5个沼气池细菌和真菌的物种注释的运算分类单位(OTU)数目,其中细菌OTU数为2105,其相同的OTU数为225;真菌OTU的总数为2224,其相同的OTU数为178。以牛粪为底物的沼液样品A08,A09,A010细菌门相对丰度由高到低分别是拟杆菌门、厚壁菌门和变形菌门。以鸡粪为底物的沼液A011的细菌门主要是拟杆菌门和厚壁菌门,其相对丰度分别为58.5%和23.8%。以猪粪为底物的样品A012细菌门相对丰度由高到低分别是厚壁菌门、拟杆菌门和变形菌门。5种沼液样品中的主要真菌门是子囊菌门和担子菌门,其中子囊菌门占多数,相对丰度为72.7%～83.3%,担子菌门的相对丰度为4.3%～7.3%。新疆不同地区和不同底物的沼气微生物种类有很大不同,研究其不同微生物结构为制备高效沼气发酵菌剂提供了参考。     

Detection of intestinal parasites in pig slurry: A preliminary study from five farms in Spain

The aim of this study was to investigate the presence of intestinal parasites in pig slurries from several piggeries in Alicante (Spain). Pig slurries were collected in five highly-intensive pig farms (A–E), being sampled in each farm from the pits depending on the production cycle (gestating sows, farrowing sows, weaners, finishers). Samples were concentrated either through zinc sulphate flotation or by formalin–ethyl acetate sedimentation methods. Parasitological examination was performed by optical microscopy. Detection of Cryptosporidium sp. was performed using conventional acid-fast stain and by DNA extraction and PCR amplification. Cryptosporidium genus-specific primers (CPBDIAGF and CPBDIAGR) were used to amplify the Cryptosporidium SSU-rRNA variable region. Intestinal parasites were found in all farms studied. Several protozoa (Ballantidium coli, Entamoeba coli and Cryptosposidium sp.) and helminths (Ascaris suum, Trichuris suis, Fasciola hepatica, Strongylida and nematode larvae) were identified. Parasite viability studies are needed in order to assess the potential risk for animal and human health.     

Potential health risks associated with the persistence of Escherichia coli O157 in agricultural environments

Abstract. Escherichia coli serotype O157 is a virulent human pathogen the global incidence of which has increased. It has been demonstrated that cattle are the primary reservoir of this pathogen. This has serious implications for the land-based disposal of organic wastes such as cattle manure, cattle slurry and abattoir waste. Further, it also has serious ramifications for the protection of surface and groundwater drinking supplies and public access to pasture land. However, while soil and vegetation can be expected to directly influence the survival of this pathogen, there is a paucity of information concerning the behaviour and survival of E. coli O157 in agricultural environments. It appears that E. coli O157 presently contaminates between 1 to 15% of UK cattle herds, depending on region, and that faecal excretion of the bacterium shows a distinct seasonality which also reflects the incidence of human infections. E. coli O157 can remain viable in soil for greater than 4 months and appears to be a highly resilient pathogen possessing the capability to adapt easily to environmental stresses. While most human cases of E. coli O157 related food poisoning have been associated with the consumption of contaminated meat and dairy products, there is also evidence that human infection has occurred through the ingestion of contaminated soil, fruit and vegetables and drinking water. In this review the potential threat to human health posed by the application of contaminated organic wastes to soil and possible strategies for reducing the amount of pathogen entering the food chain are highlighted.     

基于物理指标快速预测猪粪尿肥料成分含量的试验研究

该试验旨在研究家畜粪便的物理指标与其肥料成分含量的关系，用来预测猪粪便肥料成分含量。通过对鲜粪便的理化指标测定的试验数据进行统计分析后提出，电导仪和密度计两种实验室常用仪器可实现对猪粪便中肥料成分氮、磷、钾含量的预测：用电导率这一物理指标可准确预测猪粪、猪尿和粪尿混合物中铵态氮的含量，同时可准确预测猪粪、猪尿和粪尿混合物中钾的含量；用密度这一物理指标可较准确地预测猪粪、猪尿和粪尿混合物中总氮的含量，同时可较准确地预测猪粪尿混合物中磷的含量。分析中发现猪尿中总氮和铵态氮比例基本稳定，由此推想用电导率来预测猪